Inquiring Mind
Active Member
Any reason to know a Manifold Air Pressure value while flying gyro with 915iS and fixed pitch prop ?
Thanks.
Thanks.
On any turbo charged engine it’s good to know your MAP or boostAny reason to know a Manifold Air Pressure value while flying gyro with 915iS and fixed pitch prop ?
Thanks.
What do I use it for? I can't control the mixture, I can't control the prop pitch, or boost, so what good does knowledge of MAP do to me? I have an indicator onboard, which I have no idea how to use, so do I really need it?On any turbo charged engine it’s good to know your MAP or boost
You better learn the limitations of your power plant and MAP or you can over boost the engine and shorten its TBO. or wreck it all together.What do I use it for? I can't control the mixture, I can't control the prop pitch, or boost, so what good does knowledge of MAP do to me? I have an indicator onboard, which I have no idea how to use, so do I really need it?
Well if the waste gate or its controller gets stuck and you boost for a period beyond the engines specified times you will hurt the motor, bend the crank if your lucky, or you may find a rod through the piston with overboost.What do I use it for? I can't control the mixture, I can't control the prop pitch, or boost, so what good does knowledge of MAP do to me? I have an indicator onboard, which I have no idea how to use, so do I really need it?
What do I use it for? I can't control the mixture, I can't control the prop pitch, or boost, so what good does knowledge of MAP do to me? I have an indicator onboard, which I have no idea how to use, so do I really need it?
Well this is a interesting topic, I teach a student who is working with say an M16 ...RAM.... this pre lift check is quick and informative R= rotor speed , A= airspeed as we run down the runway , M MAP = 35 ....before moving throttle right and to the turbo cos then I want to see it’s reflecting 40 ...this tells me the engine is making power and workingShort answer given the basics of the aircraft is no you don't need it. Throttle position is all you can do to control the elements others have highlighted.
I can affect manifold pressure with the throttle.What do I use it for? I can't control the mixture, I can't control the prop pitch, or boost, so what good does knowledge of MAP do to me? I have an indicator onboard, which I have no idea how to use, so do I really need it?
No doubt but the 915 will alarm when it isn't.in my opinion based on my experience to assume the waste gate and electronic control systems on a turbocharged engine will work flawlessly is an unreasonable fantasy.
.... and to my point about differences training.... beyond which an alarm is binary. Its on or off. It is an attention getter. As you may know from the POH the 915 pre flight check includes a function check of both lanes that ensure said attention getter is operational.Many people prefer lights and alarms to instruments.
I prefer instruments so I can see a problem developing, have a sense of how urgent the problem is and I can see how a change affects things.
The 915 I flew had panels that I found confusing in an instrument sweep and they prolonged the sweep and reduced the value.
I am sure with more experience I would become more comfortable and less confused.
MAP is representative of the power being made by the engine at a particular engine rpm and in my opinion is a better representation than engine rpm alone.Perhaps I can now learn something about the importance of the manifold pressure in a turbocharged engine...
If I understand it correctly, in an 'aspirated' engine, the depression in the intake, at a given rpm, is proportional to the load. That depression is high (the intake pressure is much lower than the atmospheric) when the load is small, and it drops (the intake pressure gets closer to the atmospheric) as the load rises.
But with supercharging continually increasing the intake pressure, is still MAP a measure of the engine load...?
Reduce throttle and work to discover the underlying problem if it was high and land if it was low.OK. In the end 915 generated alarm or MAP out of expected range on a gauge... what you going to do?
MAP is representative of the power being made by the engine at a particular engine rpm and in my opinion is a better representation than engine rpm alone.
In other words if I was going somewhere I would be more inclined to use MAP and engine rpm than simply picking a particular engine rpm.
With power on landings I find using MAP more consistent than picking an engine rpm.
Nobody said that. Who's fantasy is this?In my opinion based on my experience to assume the all the electronic alarms on a turbocharged engine will work flawlessly is an unreasonable fantasy.
Are you checking MAP while on final, really?With power on landings I find using MAP more consistent than picking an engine rpm.
Are you checking MAP while on final, really?